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Title: Generic Repository Concepts and Thermal Analysis for Advanced Fuel Cycles - 12477

Abstract

A geologic disposal concept for spent nuclear fuel (SNF) or high-level waste (HLW) consists of three components: waste inventory, geologic setting, and concept of operations. A set of reference geologic disposal concepts has been developed by the U.S. Department of Energy (DOE), Used Fuel Disposition campaign. Reference concepts are identified for crystalline rock, clay/shale, bedded salt, and deep borehole (crystalline basement) geologic settings. These were analyzed for waste inventory cases representing a range of waste types that could be produced by advanced nuclear fuel cycles. Concepts of operation consisting of emplacement mode, repository layout, and engineered barrier descriptions, were selected based on international progress. All of these disposal concepts are enclosed emplacement modes, whereby waste packages are in direct contact with encapsulating engineered or natural materials. Enclosed modes have less capacity to dissipate heat than open modes such as that proposed for a repository at Yucca Mountain. Thermal analysis has identified important relationships between waste package size and capacity, and the duration of surface decay storage needed to meet temperature limits for different disposal concepts. For the crystalline rock and clay/shale repository concepts, a waste package surface temperature limit of 100 deg. C was assumed to prevent changes in clay-basedmore » buffer material or clay-rich host rock. Surface decay storage of 50 to 100 years is needed for disposal of high-burnup LWR SNF in 4-PWR packages, or disposal of HLW glass from reprocessing LWR uranium oxide (UOX) fuel. High-level waste (HLW) from reprocessing of metal fuel used in a fast reactor could be disposed after decay storage of 50 years or less. For disposal in salt the rock thermal conductivity is significantly greater, and higher temperatures (200 deg. C) can be tolerated at the waste package surface. Decay storage of 10 years or less is needed for high-burnup LWR SNF in 4-PWR packages, while 12-PWR packages could be emplaced after 40 years or less. HLW from reprocessing LWR UOX fuel or metal fuel from fast reactors, could be disposed of in salt after 10 to 50 years of decay storage depending on the specific composition and other factors. For the deep borehole disposal concept no near-field temperature limits are recognized because no performance credit is taken for waste form or waste package integrity, or containment by the near-field host rock. These results show the key differences in thermal management strategies available to the U.S. repository program, given the range of disposal concepts. A host medium such as salt with greater thermal conductivity and peak temperature tolerance could shorten decay storage by 50 years, or facilitate the use of larger waste packages. The LWR UOX SNF evaluated in this study represents that which could be produced in the coming decades. The existing, lower burnup used fuel that is presently in storage at many LWR locations across the U.S. is significantly cooler, and analyses of this type could be used to show that disposal is possible with less decay storage or larger waste packages. We note that while the temperature limits and waste package capacities used in this study are similar to those used internationally and in past U.S. studies, they might be increased as the result of ongoing research and development activities. This study selected enclosed emplacement modes to conform with disposal concepts developed internationally and previously in the U.S. Open modes (such as that proposed for a repository at Yucca Mountain) afford additional flexibility in waste management and the necessary investment, because the same facility serves both storage and disposal functions. Use of open modes, and combined analysis of storage, transportation, and disposal functions, are appropriate to consider in future studies of this type. (authors)« less

Authors:
 [1];  [2];  [3]; ; ;  [4];  [5]
  1. Sandia National Laboratories, P.O. Box 5800 MS 0736, Albuquerque, NM 87185 (United States)
  2. Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808 (United States)
  3. Savannah River National Laboratory, Savannah River Site, Aiken, SC 29808 (United States)
  4. Lawrence Livermore National Laboratory (United States)
  5. Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States)
Publication Date:
Research Org.:
WM Symposia, 1628 E. Southern Avenue, Suite 9-332, Tempe, AZ 85282 (United States)
OSTI Identifier:
22293702
Report Number(s):
INIS-US-14-WM-12477
TRN: US14V1358115226
Resource Type:
Conference
Resource Relation:
Conference: WM2012: Waste Management 2012 conference on improving the future in waste management, Phoenix, AZ (United States), 26 Feb - 1 Mar 2012; Other Information: Country of input: France; 17 refs.
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; CLAYS; DECAY; FAST REACTORS; HIGH-LEVEL RADIOACTIVE WASTES; IGNEOUS ROCKS; OPERATION; PWR TYPE REACTORS; REPROCESSING; SPENT FUELS; THERMAL ANALYSIS; THERMAL CONDUCTIVITY; URANIUM OXIDES; WASTE FORMS; WASTE MANAGEMENT; YUCCA MOUNTAIN

Citation Formats

Hardin, Ernest, Blink, James, Carter, Joe, Fratoni, Massimiliano, Greenberg, Harris, Sutton, Mark, and Howard, Robert. Generic Repository Concepts and Thermal Analysis for Advanced Fuel Cycles - 12477. United States: N. p., 2012. Web.
Hardin, Ernest, Blink, James, Carter, Joe, Fratoni, Massimiliano, Greenberg, Harris, Sutton, Mark, & Howard, Robert. Generic Repository Concepts and Thermal Analysis for Advanced Fuel Cycles - 12477. United States.
Hardin, Ernest, Blink, James, Carter, Joe, Fratoni, Massimiliano, Greenberg, Harris, Sutton, Mark, and Howard, Robert. 2012. "Generic Repository Concepts and Thermal Analysis for Advanced Fuel Cycles - 12477". United States.
@article{osti_22293702,
title = {Generic Repository Concepts and Thermal Analysis for Advanced Fuel Cycles - 12477},
author = {Hardin, Ernest and Blink, James and Carter, Joe and Fratoni, Massimiliano and Greenberg, Harris and Sutton, Mark and Howard, Robert},
abstractNote = {A geologic disposal concept for spent nuclear fuel (SNF) or high-level waste (HLW) consists of three components: waste inventory, geologic setting, and concept of operations. A set of reference geologic disposal concepts has been developed by the U.S. Department of Energy (DOE), Used Fuel Disposition campaign. Reference concepts are identified for crystalline rock, clay/shale, bedded salt, and deep borehole (crystalline basement) geologic settings. These were analyzed for waste inventory cases representing a range of waste types that could be produced by advanced nuclear fuel cycles. Concepts of operation consisting of emplacement mode, repository layout, and engineered barrier descriptions, were selected based on international progress. All of these disposal concepts are enclosed emplacement modes, whereby waste packages are in direct contact with encapsulating engineered or natural materials. Enclosed modes have less capacity to dissipate heat than open modes such as that proposed for a repository at Yucca Mountain. Thermal analysis has identified important relationships between waste package size and capacity, and the duration of surface decay storage needed to meet temperature limits for different disposal concepts. For the crystalline rock and clay/shale repository concepts, a waste package surface temperature limit of 100 deg. C was assumed to prevent changes in clay-based buffer material or clay-rich host rock. Surface decay storage of 50 to 100 years is needed for disposal of high-burnup LWR SNF in 4-PWR packages, or disposal of HLW glass from reprocessing LWR uranium oxide (UOX) fuel. High-level waste (HLW) from reprocessing of metal fuel used in a fast reactor could be disposed after decay storage of 50 years or less. For disposal in salt the rock thermal conductivity is significantly greater, and higher temperatures (200 deg. C) can be tolerated at the waste package surface. Decay storage of 10 years or less is needed for high-burnup LWR SNF in 4-PWR packages, while 12-PWR packages could be emplaced after 40 years or less. HLW from reprocessing LWR UOX fuel or metal fuel from fast reactors, could be disposed of in salt after 10 to 50 years of decay storage depending on the specific composition and other factors. For the deep borehole disposal concept no near-field temperature limits are recognized because no performance credit is taken for waste form or waste package integrity, or containment by the near-field host rock. These results show the key differences in thermal management strategies available to the U.S. repository program, given the range of disposal concepts. A host medium such as salt with greater thermal conductivity and peak temperature tolerance could shorten decay storage by 50 years, or facilitate the use of larger waste packages. The LWR UOX SNF evaluated in this study represents that which could be produced in the coming decades. The existing, lower burnup used fuel that is presently in storage at many LWR locations across the U.S. is significantly cooler, and analyses of this type could be used to show that disposal is possible with less decay storage or larger waste packages. We note that while the temperature limits and waste package capacities used in this study are similar to those used internationally and in past U.S. studies, they might be increased as the result of ongoing research and development activities. This study selected enclosed emplacement modes to conform with disposal concepts developed internationally and previously in the U.S. Open modes (such as that proposed for a repository at Yucca Mountain) afford additional flexibility in waste management and the necessary investment, because the same facility serves both storage and disposal functions. Use of open modes, and combined analysis of storage, transportation, and disposal functions, are appropriate to consider in future studies of this type. (authors)},
doi = {},
url = {https://www.osti.gov/biblio/22293702}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jul 01 00:00:00 EDT 2012},
month = {Sun Jul 01 00:00:00 EDT 2012}
}

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